Robust Control of Constrained and Unconstrained Robot Manipulators

Abstract

In this paper, a robust controller is developed for the position and force tracking of a single n-joint nonredundant manipulator. The control strategy is shown to apply when the manipulator is unconstrained and when it is constrained by a rigid environment. Starting with the model of the robot dynamics and constraints in joint space, a transformed dynamic equation is developed with respect to a set of task space coordinate variables. Using this transformed system, a control strategy is developed for the manipulator which is robust with respect to the uncertainty in the system. For the proposal control strategy, the position tracking error is shown to be globally exponentially stable (GES) while the force tracking error is shown to be inversely proportional to the force control feedback gains.